Target search apparatus for homing torpedoes



July 25, 1967 F. P. FlNLON ETAL 3,332,382

TARGET SEARCH APPARATUS FOR HOMING TORPEDOES Filed Sept. 16. 1959VERTICAL GYRO FRANCIS P. FINLON EDWARD DAWSON INVENTORS A TORNEYS UnitedStates Patent 3,332,382 TARGET SEARCH APPARATUS FOR HOMING TORPEDOESFrancis P. Finlon, State College, and Edward Dawson, Ambler, Pa.,assignors, by mesne assignments, to the United States of America asrepresented by the Secretary of the Navy Filed Sept. 16, 1959, Ser. No.840,480 4 Claims. (Cl. 11420) This invention relates to torpedoes and,more particularly, to a target search apparatus for homing torpedoes.

In acoustic or signal-guided torpedoes, the rudder and elevator aredeflected in accordance with information derived from signals which maybe of audio or supersonic frequency, emanating from the target.Alternately, a signal may be produced by the torpedo and be reflectedback from the target. Generally, the control of the rudder and elevatoris affected by way of a control circuit, wherein the signal received byhydrophones mounted within the torpedo is resolved to a control signal,in accordance with the polarity of which the rudder and elevators aredeflected in one direction or another to steer the torpedo to thetarget.

This type of torpedo is often dropped by aircraft in an area where anenemy submarine is thought to be located, where under its own power itwill seek out, home upon and destroy the target submarine. Generally,the acoustic search lobe or search beam extends directly forward, andhence the torpedo must be pointed nearly at the target for detection tobe made. To give the torpedo an opportunity to direct its search lobeinto all portions of the surrounding sea, it is generally programmed todescribe a cylindrical helix downward from the surface of the water. Inthis way a cylindrical volume is searched during its downward path.

One of the greatest disadvantages of this method of search is that theacoustic detecting range of the torpedo is limited substantially by theflow noise produced by water passing in the proximity of the hydrophonearray. This noise is estimated to be proportional to the fourth power ofthe torpedos velocity. Another disadvantage to this method is thatduring the entire search, the torpedo is proceeding under its own power,consuming propellant and hence reducing the amount remaining forattacking the target. This invention proposes to eliminate thesedifficulties by providing means for a quiet acoustical search withoutuse of the torpedos main propelling means in which the time of deliveryto the target area and searching time are in all ways equivalent to thepreviously-described method.

These results are obtained without reduction of any tactical performancecharacteristics such as vertical or azimuth search rate, volume searchrate, or delay by providing a sea water jet and control system whichrotate the torpedo in a horizontal plane while it is sinking or risingat a predetermined rate. In this manner the acoustic search lobe of thehydrophone array has an opportunity to scan all depth of surrounding seaas the torpedo proceeds in its downward path. By this means, theself-noise of the torpedo is reduced to almost zero and hence, the rangeof the acoustical search system is extended considerably.

It is therefore an object of this invention to provide a device for anacoustic homing torpedo which will permit a noiseless and effectiveacoustical search at distant ranges.

Another object of this invention is to provide a device for use on anacoustic homing torpedo which will not utilize a significant portion ofthe propellant fuel during the searching operation.

Another object of this invention is to provide a relatively noiselessmeans of maintaining a torpedo in a horiice zontal position in the waterand rotating it at a desired angular velocity while it proceeds in avertical direction.

Other objects and a fuller understanding of the invention may be had byreferring to the following description and claims taken in conjunctionwith the accompanying drawings in which:

FIGURE 1 is a longitudinal view of the torpedo embodying the features ofthe present invention.

FIGURE 2 is an enlarged diagrammatic cross-sectional view taken alongline 22 of FIGURE 1 in the direction of the arrows.

FIGURE 3 is a functional diagram of the valve and related componentsassociated with this invention.

Referring now to the drawings, the torpedo 10 illustrated in FIGURE 1 iscomprised of a shell 12 of conventional design provided with head 14containing a hydrophone search array, well known in the art (not shown)and a propeller 16 attached to its rearward-most portion to propel thetorpedo in a forwardly direction by conventional means. Elevator 18 andrudder 20 respond to internal torpedo controls (not shown) to direct thetorpedo 10 in a horizontal or vertical direction depending upon thecommands given. Upper outlet port 22 and lower outlet port 24 arepositioned laterally in the rearward portion of the torpedo for theejection of sea water.

Referring to FIGURE 2, upper and lower outlet ports 22 and 24 are incommunication with valve 26 through upper ejection tube 28 and lowerejection tube 30. Valve 26, in turn, communicates through transversetube 32 with a conventional constant flow pump 34. Pump 34 in turn isconnected through intake tube 38 with inlet port 36 which is positionedon the lateral portion of the torpedo shell 12 on the side opposite tooutlet ports 22 and 24.

FIGURE 3 shows in detail the operation of valve 26. Valve 26,represented in schematic, is the three-way type so designed that aslight actuation, as for example turning in a clockwise direction, willallow increased flow through lower ejection tube 30 and restrict theflow through upper ejection tube 28. Vertical gyro 40 is of theconventional type, well known in the art, designed to detect angulardisplacement of the torpedo from a horizontal plane and to transmit asignal voltage proportional to such angular displacement through gyroleads 42 to amplifier 44. Amplifier 44 is designed to transmit currentsignals proportional to the voltage signals received. Thus a signal fromvertical gyro 40 indicating a change in pitch from above to below thehorizontal will cause amplifier 44 to reverse the flow of currentthrough amplifier leads 46. Solenoid 48, whose coil 50 is connected toamplifier leads 46, is of the rotary type, comprised of armature 52extending through coil 50, disc 54 integrally connected to armature 52.Disc 54 is supported on supports 56 by ball-bearings 58 which arepositioned in upper inclined races 60 of disc 54 and lower inclined race62 of support 56, and are so adapted that a movement of armature 52along its longitudinal axis will cause armature 52 and attached disc 54to rotate. Thus, a current signal from amplifier 44 through amplifierleads 46 and coil 50 will cause clockwise rotation of armature 52 (asseen from above) in the case of an upward pitch of the'torpedo, as whenhead 14 is higher than propellel 16, and a counter-clockwise rotationwhen the torpedo is in a head-down position. Spring 64 integrallyconnected with disc 54 and spring support 66 positions armature 52neutrally when no current is flowing through coil 50. Armature 52 ismechanically linked to Valve 26,

as indicated by the dotted line, in such a manner that clockwiserotation of armature 52 will cause valve 26 to increase the water flowthrough lower ejection tube 30 and decrease the flow through upperejection tube 28. A counter-clockwise turn of the armature will have theopposite effect.

In operation, the torpedo is projected into the search area by aircraftdrop or other means. On entering the water, the propulsion systemremains unactivated while the apparatus of this invention and thehydrophone search array (not shown) in head 14, operate. Sea waterenters intake tube 38 through inlet port 36, proceeds to pump 34 whereit is pumped through transverse tube 32 to valve 26 and from there outof the torpedo shell 12 through upper and lower ejection tubes 28 and30, and outlet ports 22 and 24. Outlet ports 22 and 24 are positioned ata dis tance to the rear of the torpedo so that a sufficient mo ment armis produced by the reaction of the emerging water jets to cause thetorpedo to turn about a point within its physical structure. The torpedois so trimmed by methods well known in the art, that the outlet jets 22and 24 will seek a lateral position while the torpedo is in the water.Generally, the torpedo is made less buoyant than Water so that it willsink at a predetermined rate for optimum search while it is rotatingabout a point within.

If, in sinking, the longitudinal axis of the torpedo should vary inpitch from the horizontal, say head 14 becomes lower than propeller 16,vertical gyro 40 activates to send an electrical voltage signal, throughgyro leads 42 to amplifier 44, which transmits a current flowproportional to the voltage signal through amplifier leads 46 to coil 50of rotary solenoid 48. This current causes armature 52 to move away fromcoil 50, and guided by ballbearings 58 of upper and lower races 60 and62 to rotate in a counter-clockwise direction. Valve 26 mechanicallylinked to armature 52 as indicated by the dotted lines, would likewisemove in a counter-clockwise direction, allowing a proportional increasein water flow to pass through upper ejection tube 28 and a proportionaldecrease to pass through lower ejection tube 30. The vertical componentof the increased jet emitted by upper outlet port 22 would tend to forcethe rearward portion of the torpedo downwardly relative to the forwardportion and thus correct the change in pitch of the torpedo fromhorizontal.

During this horizontal correction, the horizontal reaction components ofthe water jets forces the torpedo to rotate about a point within. Whenthe torpedos longitudinal axis has regained its horizontal position, theoutput of the vertical gyro 40 approaches zero and solenoid 48 isunenergized. Spring 64 then positions armature 52 and valve 26 in aneutral position such that equal quantities of water flow from upper andlower outlet ports 22 and 24. By this mechanism, the torpedo is keptrotating in a horizontal plane and at the same time sinks in the mannerpreviously described.

As a torpedo sinks and rotates the activated hydrophone array andrelated equipment (not shown) directionally searches, by acoustic means,the area forward of head 14. The detection capabilities of the targetsare increased substantially by reducing the forward velocity of thetorpedo essentially to zero by the employment of the proposed device sothat, in most cases, detection may be made at nearly double the range ofthat possible if the torpedo was being propelled by its main propellantsystem.

Should a target be detected at any point in the torpedos descent, thecontrol apparatus (not shown) will immediately activate the propulsionsystem, deactivate pump 34 and direct the torpedo to home upon thetarget. If no target is detected by the time the torpedo reaches thebottom or any predetermined depth, the control apparatus may beprogrammed to cause the torpedo to become more buoyant than water andhence, to rise. This is accomplished by methods well known in the art,as for example, by blowing sea water from internal tanks (not shown). Inrising, the torpedo continues to rotate in a horizontal plane propelledby the device of this invention and continues its search. Alternately,upon reaching the predetermined depth, the torpedo propulsion system maybe programmed to deactivate pump 34, activate the normal propulsionsystem and direct the torpedo to another area where a second similarsearch is conducted.

While the present invention has been described in its preferredembodiment, it is realized that modification may be made and it isdesired to be understood that no limitations on the invention areintended other than the scope of the appended claims.

Having now described our invention, what we claim is new and desire tosecure by Letters Patent of the United States is:

1. In a homing torpedo adapted for acoustical search by proceedingwithout horizontal movement in a vertical direction while rotating abouta point within its physical structure, the combination comprising: aninlet port laterally positioned on said torpedo adapted for the ingressof sea water; a marine pump in communication with said inlet portadapted to propelling sea Water from without said torpedo through saidinlet port; a rotary valve in communication with said pump adapted todivert the water flow from said pump into two streams whereby the volumeof said flow through in each stream may be varied by the rotation ofsaid rotary valve; a first and a second outlet port in communicationwith said rotary valve laterally positioned on said torpedo at an acuteangle; a rotary solenoid mechanically connected to said rotary valveadapted to rotate said valve clockwise and counterclockwise in responseto electrical impulses received by said rotary solenoid; amplifier meansadapted to transmit current signals to said rotary solenoid proportionalto voltage signals received; gyroscope means adapted to sense the changein pitch of said torpedo from the horizontal plane and electricallytransmit voltage signals proportional to the angular displacement ofsaid gyroscopic means to said amplifier means whereby the flow of waterthrough said first and second outlet ports is varied to cause saidtorpedo to remain in a horizontal plane while proceeding solely in avertical direction.

2. The combination as claimed in claim 1 in which said rotary valve iscomprised of in combination: an inlet passage, a rotatable member incommunication with said inlet passage; two outlet passages incommunication with said rotatable member; a Y-shaped bore through saidrotatable member in communication with said inlet passage and said twooutlet passages whereby the rotation of said rotatable member willvariably increase the flow of sea water through one of said two outletpassages and simultaneously decrease the flow through the other of saidpassages.

3. The combination as claimed in claim 2 in which said solenoid iscomprised of in combination: a support member; a rotatable armaturemember supported upon said support member; ball bearing means positionedbetween said support member and said rotatable armature member; abiasing spring mechanically connected to said armature member adapted toneutrally position said armature member; an electrical activating coilpositioned about said armature member whereby current signals throughsaid coil cause said armature member to rotate clockwise orcounterclockwise in response to said signals.

4. In a homing torpedo adapted for acoustical search by proceedingwithout horizontal movement in a vertical direction, the combinationcomprising: an inlet port; a pump in communication with said inlet port;valve means communicating with said pump; first and second outlet portsin communication with said valve means, laterally positioned on one sideof said torpedo insuring the necessary rotation for search, said firstoutlet port being inclined at an upward angle, and said second outletport being inclined at a downward angle; means to sense change in thepitch of said torpedo from the horizontal plane associated with saidvalve means, said means comprised of a vertical gyro, an amplifier inelectrical combination 5 6 with said vertical gyro, a rotating solenoidelectrically 1,382,166 6/1921 Blum 1l420 connected to said amplifier,said solenoid adapted to actu- 1,825,161 9/1931 Sacco ll420 ate saidvalve whereby the flow of water from said first 2,822,755 2/1958 Edwardset al. and second outlet ports is controlled to cause said torpedo toremain in a horizontal plane, 5 BENJAMIN A. BORCHELT, Primary Examiner.

CHESTER L. JUSTUS, SAMUEL FEINBERG, References Cited Examiners UNITEDSTATES PATENTS D. G. REDINBAUGH, A. E. HALL, T. A. ROBINSON,

726,796 4/1903 Fischhaber 114-23 825,881 7/1906 Gibon 11423 10 P. A.SHANLEY, Assistant Examiners.

1. IN A HOMING TORPEDO ADAPTED FOR ACOUSTICAL SEARCH BY PROCEEDINGWITHOUT HORIZONTAL MOVEMENT IN A VERTICAL DIRECTION WHILE ROTATING ABOUTA POINT WITHIN ITS PHYSICAL STRUCTURE, THE COMBINATION COMPRISING: ANINLET PORT LATERALLY POSITIONED ON SAID TORPEDO ADAPTED FOR THE INGRESSOF SEA WATER; A MARINE PUMP IN COMMUNICATION WITH SAID INLET PORTADAPTED TO PROPELLING SEA WATER FROM WITHOUT SAID TORPEDO THROUGH SAIDINLET PORT; A ROTARY VALVE IN COMMUNICATION WITH SAID PUMP ADAPTED TODIVERT THE WATER FLOW FROM SAID PUMP INTO TWO STREAMS WHEREBY THE VOLUMEOF SAID FLOW THROUGH IN EACH STREAM MAY BE VARIED BY THE ROTATION OFSAID ROTARY VALVE; A FIRST AND A SECOND OUTLET PORT IN COMMUNICATIONWITH SAID ROTARY VALVE LATERALLY POSITIONED ON SAID TORPEDO AT AN ACUTEANGLE; A ROTARY SOLENOID MECHANICALLY CONNECTED TO SAID ROTARY VALVEADAPTED TO ROTATE AND VALVE CLOCKWISE AND COUNTERCLOCKWISE IN RESPONSETO ELECTRICAL IMPULSES RECEIVED BY SAID ROTARY SOLENOID; AMPLIFIER MEANSADAPTED TO TRANSMIT CURRENT SIGNALS TO SAID ROTARY SOLENOID PROPORTIONALTO VOLTAGE SIGNALS RECEIVED GYROSCOPE MEANS ADAPTED TO SENSE THE CHANGEIN PITCH OF SAID TORPEDO FROM THE HORIZONTAL PLANE AND ELECTRICALLYTRANSMIT VOLTAGE SIGNALS PROPORTIONAL TO THE ANGULAR DISPLACEMENT OFSAID GYROSCOPIC MEANS TO SAID AMPLIFIER MEANS WHEREBY THE FLOW OF WATERTHROUGH SAID FIRST AND SECOND OUTLET PORTS IS VARIED TO CAUSE SAIDTORPEDO TO REMAIN IN A HORIZONTAL PLANE WHILE PROCEEDING SOLELY IN AVERTICAL DIRECTION.